MEMS devices are small movable mechanical structures advantageously constructed using semiconductor processing methods. Oftentimes MEMS devices are provided as actuators and have proven quite useful in a wide variety of applications.
A MEMS actuator is oftentimes configured and disposed in a cantilever fashion. Accordingly, it thus has an end attached to a substrate and an opposite free end suspended above the substrate. The free end is movable between at least two positions, one being a neutral position and the other(s) being deflected positions.
Common actuation mechanisms used in MEMS actuators include electrostatic, magnetic, piezo and thermal, the last of which is the primary focus of the improvements presented hereafter. The deflection of a thermal MEMS actuator results from a potential being applied between a pair of terminals—commonly called “anchor pads” in the art—which potential causes a current flow elevating the temperature of the structure. This in turn causes a part thereof to either elongate or contract, depending upon the particular material(s) used.
A known use of thermal MEMS actuators is to configure them as switches. Such MEMS switches offer numerous advantages over alternatives and in particular, they are extremely small, relatively inexpensive, consume little power and exhibit short response times.
Examples of MEMS actuators and switches can be found in U.S. Pat. No. 7,036,312 issued May 2, 2006 to Stephane MENARD et al., which patent is hereby incorporated by reference.
Given the importance of thermally actuated MEMS devices, new designs enhancing their performance, reliability and/or manufacturability always represent a significant advance in the art.